1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, 13 * software distributed under the License is distributed on an 14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 15 * KIND, either express or implied. See the License for the 16 * specific language governing permissions and limitations 17 * under the License. 18 */ 19 package org.apache.myfaces.shared_orchestra.util; 20 21 import java.util.HashMap; 22 import java.util.Map; 23 import java.util.Set; 24 import java.util.Iterator; 25 26 27 /** 28 * @author Anton Koinov (latest modification by $Author: grantsmith $) 29 * @version $Revision: 472630 $ $Date: 2006-11-08 15:40:03 -0500 (Wed, 08 Nov 2006) $ 30 */ 31 public class HashMapUtils 32 { 33 //~ Constructors ------------------------------------------------------------------------------- 34 35 protected HashMapUtils() 36 { 37 // block public access 38 } 39 40 //~ Methods ------------------------------------------------------------------------------------ 41 42 /** 43 * Calculates initial capacity needed to hold <code>size</code> elements in 44 * a HashMap or Hashtable without forcing an expensive increase in internal 45 * capacity. Capacity is based on the default load factor of .75. 46 * <p> 47 * Usage: <code>Map map = new HashMap(HashMapUtils.calcCapacity(10));<code> 48 * </p> 49 * @param size the number of items that will be put into a HashMap 50 * @return initial capacity needed 51 */ 52 public static final int calcCapacity(int size) 53 { 54 return ((size * 4) + 3) / 3; 55 } 56 57 /** 58 * Creates a new <code>HashMap</code> that has all of the elements 59 * of <code>map1</code> and <code>map2</code> (on key collision, the latter 60 * override the former). 61 * 62 * @param map1 the fist hashmap to merge 63 * @param map2 the second hashmap to merge 64 * @return new hashmap 65 */ 66 public static HashMap merge(Map map1, Map map2) 67 { 68 HashMap retval = new HashMap(calcCapacity(map1.size() + map2.size())); 69 70 retval.putAll(map1); 71 retval.putAll(map2); 72 73 return retval; 74 } 75 76 /** 77 * spit out each name/value pair 78 */ 79 public static String mapToString(Map map){ 80 Set entries = map.entrySet(); 81 Iterator iter = entries.iterator(); 82 StringBuffer buff = new StringBuffer(); 83 while (iter.hasNext()) 84 { 85 Map.Entry entry = (Map.Entry) iter.next(); 86 buff.append("[" + entry.getKey() + "," + entry.getValue() + "]\n"); 87 } 88 return buff.toString(); 89 } 90 91 }